Evidence for a Photocurrent Fano Resonance in an Artificial Nanostructure

We present internal-photoemission (photocurrent) experimental evidence for a Fano resonance at an n-p GaAs homojunction with a 0.5-ML Si intralayer (delta doping). This is one of a very few cases in which Fano resonances have been observed in artificial nanostructures. Our results show that this fundamental class of phenomenona plays a relevant role in band-gap engineering, by affecting the transport and phototransport properties of delta-doping nanostructures.